Throughout the various stages of plasma processing, such as semiconductor or display manufacturing, etc., process parameters may vary. Processing conditions can change over time with changes in process parameters creating undesirable results. Small changes can occur in the composition or pressure of an etch gas, process chamber conditions, or wafer temperature. As such, plasma processing facilities require constant monitoring.
The measuring and monitoring of these process parameters at any given time permit valuable data to be accumulated and analyzed. Process control feedback may be used to adjust the process parameters or determine the viability of certain process materials. However, in many cases, changes of process data reflecting deterioration of processing characteristics cannot be detected by simply referring to the process data displayed. It is difficult to detect early stage abnormalities and characteristic deterioration of a process, and often may be necessary to obtain fault detection and prediction, as well as pattern recognition by an advanced process control (APC). Oftentimes a processing tool is not connected to an APC system and the data on the processing tool is not adequately used.